Increased expression of c-fos protein associated with increased matrix metalloproteinase-9 protein expression in the endometrium of endometriotic patients

ObjectiveTo investigate c-fos and matrix metalloproteinase-9 (MMP-9) expression in the endometrium from women with or without endometriosis throughout the menstrual cycle, and to explore the correlation of c-fos expression with MMP-9 expression and 17β-E2 levels in serum.DesignMolecular studies in human tissue.SettingA women's hospital in China.Patient(s)Fifty-five premenopausal women (25 with endometriosis and 30 without endometriosis) undergoing laparoscopic surgery or hysterectomy.Intervention(s)Eutopic and ectopic endometrium tissue were obtained at the time of surgery. Peripheral sera were also collected on the same day.Main Outcome Measure(s)Immunohistochemical localization of c-fos in the endometrium, c-fos and MMP-9 protein levels in the endometrium, and 17β-E2 levels in the serum.Result(s)c-fos protein was predominantly located in the nuclei of glandular epithelial cells and stromal cells. c-fos and MMP-9 protein levels in paired eutopic and ectopic endometria from women with endometriosis were significantly higher than those in the endometrium from women without endometriosis. No significant difference in c-fos or MMP-9 protein levels was observed between paired eutopic and ectopic endometria. c-fos protein levels in endometrium positively correlated with endometrial MMP-9 levels and serum 17β-E2 levels.Conclusion(s)Expression of c-fos in the human endometrium may be regulated by 17β-E2, and c-fos may be involved in development of endometriosis by promoting MMP-9 gene expression and subsequently the invasive potential of endometrial explants.